High energy Li/CoO/sub 2/ battery system in inorganic solution

Abstract

A new battery system Li/inorganic electrolyte/Li/sub x/CoO/sub 2/ is examined because of its high theoretical energy density of 1070 Wh/kg. This 4 V battery contains only inorganic compounds without any polymeric binders or organic separators. The battery is assembled in the discharged state in absence of metallic lithium. By first charging, Li is deintercalated and deposited at a nickel substrate. The inorganic electrolyte solution, consisting of LiAlCl/sub 4/ and SO/sub 2/, is liquid between -25 and about 70/spl deg/C with good ionic conductivity. The positive mass is made by a new high temperature process without using powders, organic binders or carbon additives. The resulting foil electrode is flexible. Potentiodynamic cycling of the Li/sub x/CoO/sub 2/ electrode between 3.5 and 4.5 V vs. Li/Li/sup +/ demonstrates the stability of the oxide in conjunction with an increase in electronic resistance with higher cycling numbers. Battery cycling, cyclic voltammetry and impedance studies are carried out to determine electrochemical processes of the electrode material. This includes especially the Li-intercalation process at the cathode.<>